1. Technical Field
The present invention relates to a recording apparatus.
2. Related Art
In a recording apparatus such as an ink jet printer, when performing a recording process on a recording medium such as recording paper, the recording medium needs to be supported by a platen in such a manner that the recording medium is in a certain position (parallel) with respect to a recording head.
Particularly, in a case where rolled paper is used as the recording medium, since the end portions of the rolled paper float from the platen due to rolling (curling), there is a recording apparatus which is provided with a paper suction section which suctions rolled paper to the platen in order to reduce floating.
The paper suction section is usually made so as to adsorb and retain (negative pressure suction) the rolled paper on the platen by providing a large number of suction holes in the platen and suctioning external air through each suction hole via a built-in fan on the rear surface side of the platen.
In the case of placing a recording medium, such as rolled paper, on the platen and transporting the medium, due to changes in the size (variations in the width direction dimension) of the recording medium, the transport state (position), or the like, the suction holes are not necessarily all covered by the recording medium. In other words, since there are suction holes in an opened state, which are not covered by the recording medium, air leaks from these suction holes (air leakage occurs).
Then, if there are a large number of suction holes in such an opened state, the adsorption force that adsorbs the recording medium is reduced, so that suppression of floating of the recording medium becomes incomplete.
For this reason, as shown in JP-A-2002-205855, a printer apparatus in which a shutter mechanism which opens and closes the large number of suction holes in a stepwise manner is provided on the rear surface side of a platen with a large number of suction holes formed therein and the shutter mechanism is operated in accordance with the transport state or the like of the recording medium is proposed.
In the invention disclosed in JP-A-2002-205855, a configuration is provided in which a flat plate-like shutter member disposed on the rear surface side of the platen is reciprocated by a cam mechanism. Then, the suction holes in the platen and the through holes in the shutter member are aligned and the area of the opening can be adjusted by altering the degree of overlap of the holes.
However, especially when applied to large-scaled printers, in the above-mentioned invention, there is a problem in that air leakage easily occurs. In order to suppress air leakage when the suction holes of the platen are closed by the shutter member, there is a need to bring the platen and the shutter member into close contact with each other. However, in large-scaled printers, since the areas of both the platen and the shutter member are large, the shutter member disposed on the rear surface side of the platen is prone to bending due to its own weight, so that it is not always easy to bring the two into close contact with each other.
Further, a structure to markedly suppress reductions in the adsorption force that adsorbs the recording medium in place has also been disclosed. This is achieved by providing a sheet covering the surface of the platen, thereby limiting the adsorption area in accordance with the width of the recording medium and blocking areas where the recording medium is not present from the surface side of the platen.
However, since a sheet is disposed covering the surface of the platen, the risk of collision or the like with a recording head should be avoided. Further, in the case of a structure in which the sheet is disposed on the pressure chamber side below the platen, thereby blocking the suction holes from the rear surface side of the platen, since rigidity and close contact are required for a structure section which partitions the suctioning area, there is a tradeoff between functionality and operability.
Further, since an existing shutter member is fabricated by performing sheet-metal working on a thin metal plate, the larger the size, the more difficult it becomes to attain flatness. If the flatness of the shutter member is low, close contact with the platen becomes poor, so that air leakage easily occurs from the suction holes.